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253 lines
6.3 KiB
C
253 lines
6.3 KiB
C
/**********************************************************************
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random.c -
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$Author$
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$Date$
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created at: Fri Dec 24 16:39:21 JST 1993
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Copyright (C) 1993-2003 Yukihiro Matsumoto
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**********************************************************************/
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/*
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This is based on trimmed version of MT19937. To get the original version,
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contact <http://www.math.keio.ac.jp/~matumoto/emt.html>.
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The original copyright notice follows.
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A C-program for MT19937, with initialization improved 2002/2/10.
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Coded by Takuji Nishimura and Makoto Matsumoto.
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This is a faster version by taking Shawn Cokus's optimization,
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Matthe Bellew's simplification, Isaku Wada's real version.
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Before using, initialize the state by using init_genrand(seed)
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or init_by_array(init_key, key_length).
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Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. The names of its contributors may not be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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Any feedback is very welcome.
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http://www.math.keio.ac.jp/matumoto/emt.html
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email: matumoto@math.keio.ac.jp
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*/
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/* Period parameters */
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#define N 624
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#define M 397
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#define MATRIX_A 0x9908b0dfUL /* constant vector a */
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#define UMASK 0x80000000UL /* most significant w-r bits */
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#define LMASK 0x7fffffffUL /* least significant r bits */
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#define MIXBITS(u,v) ( ((u) & UMASK) | ((v) & LMASK) )
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#define TWIST(u,v) ((MIXBITS(u,v) >> 1) ^ ((v)&1UL ? MATRIX_A : 0UL))
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static unsigned long state[N]; /* the array for the state vector */
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static int left = 1;
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static int initf = 0;
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static unsigned long *next;
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/* initializes state[N] with a seed */
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static void
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init_genrand(s)
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unsigned long s;
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{
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int j;
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state[0]= s & 0xffffffffUL;
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for (j=1; j<N; j++) {
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state[j] = (1812433253UL * (state[j-1] ^ (state[j-1] >> 30)) + j);
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/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
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/* In the previous versions, MSBs of the seed affect */
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/* only MSBs of the array state[]. */
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/* 2002/01/09 modified by Makoto Matsumoto */
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state[j] &= 0xffffffffUL; /* for >32 bit machines */
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}
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left = 1; initf = 1;
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}
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static void
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next_state()
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{
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unsigned long *p=state;
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int j;
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/* if init_genrand() has not been called, */
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/* a default initial seed is used */
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if (initf==0) init_genrand(5489UL);
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left = N;
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next = state;
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for (j=N-M+1; --j; p++)
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*p = p[M] ^ TWIST(p[0], p[1]);
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for (j=M; --j; p++)
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*p = p[M-N] ^ TWIST(p[0], p[1]);
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*p = p[M-N] ^ TWIST(p[0], state[0]);
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}
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/* generates a random number on [0,1)-real-interval */
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static double
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genrand_real()
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{
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unsigned long y;
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if (--left == 0) next_state();
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y = *next++;
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/* Tempering */
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y ^= (y >> 11);
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y ^= (y << 7) & 0x9d2c5680UL;
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y ^= (y << 15) & 0xefc60000UL;
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y ^= (y >> 18);
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return (double)y * (1.0/4294967296.0);
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/* divided by 2^32 */
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}
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#undef N
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#undef M
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/* These real versions are due to Isaku Wada, 2002/01/09 added */
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#include "ruby.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include <time.h>
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static int first = 1;
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static int
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rand_init(seed)
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unsigned long seed;
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{
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static unsigned long saved_seed;
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unsigned long old;
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first = 0;
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init_genrand(seed);
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old = saved_seed;
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saved_seed = seed;
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return old;
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}
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static unsigned long
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random_seed()
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{
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static int n = 0;
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struct timeval tv;
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gettimeofday(&tv, 0);
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return tv.tv_sec ^ tv.tv_usec ^ getpid() ^ n++;
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}
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static VALUE
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rb_f_srand(argc, argv, obj)
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int argc;
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VALUE *argv;
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VALUE obj;
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{
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VALUE sd;
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unsigned long seed, old;
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rb_secure(4);
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if (rb_scan_args(argc, argv, "01", &sd) == 0) {
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seed = random_seed();
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}
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else {
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seed = NUM2ULONG(sd);
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}
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old = rand_init(seed);
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return ULONG2NUM(old);
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}
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static VALUE
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rb_f_rand(argc, argv, obj)
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int argc;
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VALUE *argv;
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VALUE obj;
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{
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VALUE vmax;
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long val, max;
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rb_scan_args(argc, argv, "01", &vmax);
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if (first) {
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rand_init(random_seed());
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}
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switch (TYPE(vmax)) {
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case T_FLOAT:
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if (RFLOAT(vmax)->value <= LONG_MAX && RFLOAT(vmax)->value >= LONG_MIN) {
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max = (long)RFLOAT(vmax)->value;
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break;
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}
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vmax = rb_dbl2big(RFLOAT(vmax)->value);
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/* fall through */
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case T_BIGNUM:
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bignum:
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{
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long len = RBIGNUM(vmax)->len;
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double *buf = ALLOCA_N(double, len);
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while (len--) {
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buf[len] = genrand_real();
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}
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return rb_big_rand(vmax, buf);
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}
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case T_NIL:
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max = 0;
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break;
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default:
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vmax = rb_Integer(vmax);
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if (TYPE(vmax) == T_BIGNUM) goto bignum;
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case T_FIXNUM:
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max = NUM2LONG(vmax);
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break;
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}
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if (max == 0) {
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return rb_float_new(genrand_real());
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}
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if (max < 0) max = -max;
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val = max*genrand_real();
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return LONG2NUM(val);
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}
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void
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Init_Random()
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{
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rb_define_global_function("srand", rb_f_srand, -1);
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rb_define_global_function("rand", rb_f_rand, -1);
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}
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